• Tribology and Lubricants
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• v.17 no.4
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• pp.267-275
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• 2001

Friction and wear properties of brake friction materials containing different metal fibers (Al, Cu or Steel fibers) were investigated. Based on a simple experimental formulation, friction materials with the same amount of metal fibers were tested using a pad-on-disk type friction tester. Two different materials (gray cast iron and aluminum metal matrix composite (MMC)) were used for disks rubbing against the friction materials. Results front ambient temperature tests revealed that the friction material containing Cu fibers sliding against gray cast iron disk showed a distinct negative $\mu$-v (friction coefficient vs. sliding velocity) relation implying possible stick-slip generation at low speeds. The negative $\mu$- v relation was not observed when the Cu-containing friction materials were rubbed against the Al-MMC counter surface. Elevated temperature tests showed that the friction level and the intensity of friction force oscillation were strongly affected by the thermal conductivity and melting temperature of metallic ingredients of the friction couple. Friction materials slid against cast iron disks exhibited higher friction coefficients than Al-MMC (metal matrix composite) disks during high temperature tests. On the other hand, high temperature test results suggested that copper fibers in the friction material improved fade resistance and that steel fibers were not compatible with Al-MMC disks showing severe material transfer and erratic friction behavior during sliding at elevated temperatures.

• Journal of the Korea Institute of Building Construction
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• v.9 no.5
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• pp.145-153
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• 2009

The purpose of this research is to compare and analyze the change that must be applied to the evaluation of the slipperiness of an inclined floor, when considering its use by the physically handicapped and by the able-bodied. For this study, a simulator that can reproduce the characteristics of the body sway of a physically handicapped person was developed through a comparative experiment between able-bodied people and people with hemiplegia. In addition, as cale for the evaluation of the slipperiness of flat floors and inclined floors was composed by the sensory test result targeting physically handicapped persons (able-bodied persons wore the body sway for the handicapped and ageing in the experiment) and the able-bodied. In terms of the evaluation of the slipperiness of an inclined floor, it was evaluated that it is safe when the C.S.R' (Coefficient of Slip Resistance) of a healthy person is over 0.30, while it was evaluated that it is dangerous when the C.S.R' of a physically handicapped person is over $0.45{\sim}0.50$. Concerning this difference, it is judged that the reason for this difference is that the walking mechanism differs between an able-bodied person and a physically handicapped person.